Is there a relationship between opioid use and transient global amnesia?

BACKGROUND AND PURPOSE: Opioid-associated amnestic syndrome (OAS) and transient global amnesia (TGA) are conditions with clinical overlap. We therefore sought to determine whether opioid use might be associated with TGA. METHODS: Data from the Massachusetts Department of Public Health Syndromic Surveillance program were queried to ascertain the frequency of opioid use among emergency department (ED) encounters for TGA compared to that for all other ED visits between January 2019 and June 2023. RESULTS: A total of 13,188,630 ED visits were identified during the study period. Of 1417 visits for TGA, one visit met the exposure definition for opioid use. There were 13,187,213 visits for other indications, 57,638 of which were considered opioid-exposed. The odds ratio for the relationship between opioid use and TGA was 0.16 (95% confidence interval 0.02, 1.14). CONCLUSION: Despite the clinical overlap between OAS and TGA, surveillance data from ED visits in Massachusetts do not suggest that opioid use is a risk factor for TGA, indicating that OAS and TGA are distinct entities.

Incidence and Risk Factors of Transient Global Amnesia.

INTRODUCTION: Transient global amnesia (TGA) is a spontaneously resolving, anterograde amnesia that lasts mostly <24 h and often occurs with retrograde amnesia. The etiology of TGA remains unclear, although in recent decades, many risk factors and preceding events have been identified. There are few up-to-date reports on the TGA incidence in Northern Europe. In this study, we report the incidence and risk factors associated with TGA in Finland. MATERIALS AND METHODS: The study included all patients with suspected TGA that were referred to Kuopio University Hospital (KUH) in 2017. The hospital catchment area included 246,653 individuals. Risk factors and demographic data were collected from medical records. The TGA incidence rates were calculated as the number of patients with TGA divided by the number of individuals at risk in different age groups. RESULTS: In 2017, 56 patients were treated for TGA at KUH. Of these, 46 had a first-ever TGA. The most common event preceding TGA was physical effort (n = 28, 50%), followed by emotional stress (n = 11, 19.6%) and water contact or a temperature change (n = 11, 19.6%). The most common comorbidities were hypercholesterolemia (n = 22, 39.3%), hypertensive disease (n = 21, 37.5%), hypothyroidism (n = 11, 19.6%), coronary artery disease (n = 8, 14.3%), and migraine (n = 7, 12.5%). TGA occurred most often in December (n = 9, 16.0%), March (n = 8, 14.3%), or October (n = 8, 14.3%), and least often in November and May (n = 2, 3.6% in both months). The crude incidence of a first TGA in Eastern Finland was 18.6/100,000 inhabitants, and when standardized to the European population in 2010, it was 14.3/100,000 inhabitants. Therefore, the TGA incidence was higher than previously reported in European countries. DISCUSSION: The most common precipitating factors for TGA were physical effort, emotional stress, and water contact/temperature change. The incidence of TGA was high in the Eastern Finnish population.

Transient global amnesia - hippocampal lesions in magnetic resonance imaging.

BACKGROUND: Transient global amnesia is a benign syndrome characterized by a sudden onset loss of anterograde amnesia with full recovery. Magnetic resonance of the brain including diffusion-weighted imaging of patients with transient global amnesia revealed the presence of punctate hyperintense signal abnormalities in the hippocampus. OBJECTIVE: Analysis of the presence of hippocampal lesions in brain magnetic resonance imaging in patients with transient global amnesia and the possible influence of additional factors on their appearance. METHODS: In this retrospective, an observational study we assessed brain magnetic resonance imaging in 38 consecutive patients with transient global amnesia. The incidence of brain magnetic resonance imaging lesions was analyzed for the coexisting cardiovascular risk factors and precipitating events. RESULTS: Hippocampal brain magnetic resonance imaging lesions were detected in 47% of patients with transient global amnesia. Of those, 65% had unilateral lesions, 82% were left-sided, and 28% were right-sided. Most lesions were located in the CA1 subfield. The incidence of hypertension in patients with transient global amnesia was higher than in the general population. Stress and exercise preceded the onset of transient global amnesia only in 13% and 16% of patients, respectively. There was no higher incidence of migraine in transient global amnesia patients (13%). CONCLUSIONS: We found that nearly 50% of patients with transient global amnesia had hyperintense hippocampal brain magnetic resonance imaging lesions. In addition to hypertension, individuals with transient global amnesia had similar cardiovascular risk factors as the general population. We did not identify any precipitating events prior to the onset of transient global amnesia.

[Transient Global Amnesia in the Reykjavik area].

BACKGROUND: Transient Global Amnesia (TGA) is a benign syndrome characterized by sudden anterograde memory loss, that resolves spontaneously within 24 hours. TGA appears without other focal neurological symptoms. The aim of this study was to study TGA in the greater Reykjavik-area. METHODS: We retrospectively analysed the medical history of patients with a diagnosis of TGA (ICD-10 G45.4) at the University Hospital in Iceland in 2010-2021. Medical records were reviewed, and information about year and age at diagnosis, sex, symptoms, precipitating events, imaging results and risk factors were collected. Statistical processing was performed with Excel and Rstudio. RESULTS: Overall, 348 attacks of TGA were identified with a mean frequency of 29 attacks/year, where 9.9% had an earlier history of TGA. The mean age was 64.1, with 50% of subjects between 58-70 years old. The sex distribution was equal (49.9% female). Possible precipitating events were found in 53.7% of cases, with physical activity being the most common one (24.4%), followed by sudden temperature change and emotional stress. In 96% of patients a computerized tomography was performed (no sign of acute changes were found), and magnetic resonance imaging (MRI) in 36.2% of cases. MRI showed restricted diffusion in the hippocampal area in 10.3% of cases. DISCUSSION: TGA is not a rare but a benign syndrome. Our findings regarding age, sex distribution and precipitating events were in accordance with other studies. TGA is thought to result from a temporary hippocampal dysfunction supported by the clinical presentation and MRI findings. The cause of TGA is however still unknown.

Acute neurological disease as a trigger or co-occurrence of transient global amnesia: a case series and systematic review.

BACKGROUND: Transient global amnesia (TGA) represents a benign neurological syndrome of unknown pathophysiology, often accompanied by vanishing hippocampal punctate lesions on diffusion-weighted imaging (hippocampal punctate diffusion lesion, HPDL). The recent literature suggests that TGA may be triggered by acute neurological conditions. OBJECTIVE: To study patients with TGA triggered by an acute neurological disease. METHODS: We retrospectively reviewed patients from two neurology centres with TGA (with or without HPDL) in whom an acute neurological condition could be identified as trigger. We also performed a systematic review of the literature of this situation using predefined search terms. RESULTS: We identified 38 patients (median age 62 years, 55.3% female): 6 from our centres and 32 from the literature. Acute neurovascular diseases that preceded or were associated with TGA included ischemic and haemorrhagic strokes, convexity subarachnoid haemorrhage, and reversible cerebral vasoconstriction syndrome. As non-vascular acute neurological diseases, we identified migraine and peripheral-origin vertigo. The clinical manifestation of the neurological trigger showed a variable temporal relation with TGA onset; in some cases preceding and in others co-occurring with TGA manifestation. In some cases, presumed neurological triggers were asymptomatic and diagnosed from the neuroimaging done for the TGA. CONCLUSIONS: Acute vascular and non-vascular neurological events may trigger TGAs or may occur simultaneously. In the first case, such an acute neurological disease may activate direct pathways within the nervous systems leading to TGA, or alternatively elicit a bodily sympathetic overactivity cascade. In the second case, both neurological events may be the result of a common external stressor.

Transient Global Amnesia.

Transient global amnesia (TGA) is a clinical syndrome characterized by anterograde amnesia, mild retrograde amnesia, and confusion up to 24 hours. Most commonly seen in patients older than 50 years, TGA results from the temporary impairment of short-term memory formation. Clinically, patients have time disorientation and often ask repeated questions regarding the day's events. Vomiting, headache, blurry vision, dizziness, and nausea may be present. A physically or psychologically stressful precipitating event, such as emotional stress, significant physical exertion, exposure to extreme temperatures, high-altitude conditions, Valsalva maneuver, acute illness, or sexual intercourse, is often the cause. The pathophysiology of TGA is not well understood but may be related to impaired venous drainage of the hippocampus. The diagnosis is primarily clinical, but recent studies suggest that magnetic resonance imaging may be helpful. TGA is self-limited and resolves within 24 hours. There is no established treatment for episodes. The lifetime recurrence rate is 2.9% to 23.8%. Recent evidence suggests an association between TGA and migraine headaches as well as takotsubo cardiomyopathy. No apparent increased risk of cerebrovascular events occurs in patients who have had an episode of TGA. There is conflicting evidence as to whether an episode of TGA predisposes to future seizures or dementia.

Chronobiology of transient global amnesia.

INTRODUCTION: The etiology of transient global amnesia (TGA) is still a matter of debate. Based, among others, on the observation of a close temporal relation between certain events and subsequent TGA episodes, recent proposals discuss the relevance of stress-associated processes impacting on hippocampal functioning. Circadian, infra- and ultradian rhythmicity has been found to play a relevant role in the multifactorial pathomechanisms of various disorders but has not been thoroughly studied in TGA. METHODS: Data of patients with a final diagnosis of TGA were collected in Mannheim, Germany (06/1999-01/2018, n = 404), and in the Kansai district, Japan (04/2006-03/2018, n = 261). Chronological patterns of TGA occurrence were determined. RESULTS: Significant circadian rhythmicity of TGA occurrence with bimodal peaks (mid-morning, late afternoon) was found for the entire population (p = 0.002) and for either sub-cohort (Mannheim: p = 0.003, Kansai: p = 0.007). This finding was confirmed for either sex (women: p = 0.004, men: p = 0.004) and different age groups (< 65 years: p = 0.0009, ≥ 65 years: p = 0.003). There was no variation according to day of the week, month or season, but the proportion of patients with a weekday episode was significantly higher in the Mannheim cohort (p = 0.002). DISCUSSION: We identified a robust circadian rhythm in TGA occurrence which remarkably applied to either of the two study sites located on different continents and which was independent of sex and age. In light of abundant evidence of circadian rhythmicity of both, components of the human stress response system and memory, chronobiological analyses may provide an opportunity to further uncover the mechanisms underlying TGA.

Frequency of silent brain infarction in transient global amnesia.

BACKGROUND AND PURPOSE: To determine the frequency and distribution pattern of acute DWI lesions outside the hippocampus in patients clinically presenting with Transient Global Amnesia (TGA). METHODS: Consecutive patients clinically presenting with TGA between January 2010 and January 2017 admitted to our hospital were retrospectively evaluated. All patients fulfilled diagnostic criteria of TGA. We analyzed imaging and clinical data of all patients undergoing MRI with high-resolution diffusion-weighted imaging within 72 h from symptom onset. RESULTS: A total of 126 cases were included into the study. Fifty-three percent (n = 71/126) presented with one or more acute lesions in hippocampal CA1-area. Additional acute DWI lesions in other cortical regions were found in 11% (n = 14/126). All patients with DWI lesions outside the hippocampus presented with neurological symptoms typical for TGA (without additional symptoms.) CONCLUSIONS: In a relevant proportion of clinical TGA patients, MRI reveals acute ischemic cerebral lesions. Therefore, cerebral MRI should be performed in patients with TGA to identify a possible cardiac involvement and to detect stroke chameleons.

Migraine in transient global amnesia: a meta-analysis of observational studies.

BACKGROUND: PURPOSE: Although many studies have investigated the relationship between transient global amnesia (TGA) and migraine, to date, no meta-analysis has confirmed the existence and size of their association. METHODOLOGY: Literature search involved MEDLINE, EMBASE, CENTRAL and PsycINFO. Observational controlled studies including TGA patients (Caplan, Hodges and Warlow) were retrieved. Quality evaluation was based on the Newcastle-Ottawa scale. The prevalence of migraine was compared in TGA patients vs. healthy controls (HC), as well as in TGA against TIA individuals. Data from case-control, cross-sectional and cohort studies were pooled separately. RESULTS: Literature search yielded 1178 articles, 12 of which were included in the present meta-analysis. Results from case-control (ten), cohort (one) and cross-sectional (one) studies were compatible with an association between TGA and migraine. The nationwide inpatient cross-sectional study was of lesser value due to its inpatient orientation. The high-quality, population-based, retrospective cohort (158,301 participants per group) determined a higher relative-risk (RR) of TGA for migraine vs. non-migraine individuals [RR = 2.48, 95%confidence-interval (95% CI) = (1.32, 4.87)]. Sensitivity testing based on stricter diagnostic criteria strengthened the estimated association [RR = 3.84, 95% CI = (1.57, 9.38)]. Additionally, pooled data from eight case-control studies (700 TGA, 746 HC) yielded similar results [Odds-Ratio, OR = 2.51, 95% CI = (1.85, 3.41)], with the association mainly driven by the three high-quality studies, rather than the five articles of moderate quality. Finally, pooled findings from four case-control studies of moderate-quality revealed a higher prevalence of migraine among TGA compared to TIA patients [OR = 1.82, 95% CI = (1.22, 2.73)]. CONCLUSIONS: A significant association between TGA and migraine was established. The underlying connecting mechanism remains undetermined, yet.

Sex-related differences in stressful events precipitating transient global amnesia - A retrospective observational study.

INTRODUCTION: Physically or emotionally charged events have consistently been reported as precipitating an episode of transient global amnesia (TGA). In conjunction with evidence of hippocampal involvement from neuroimaging, this has promoted the hypothesis that TGA is a stress-related disorder. METHODS: In this retrospective observational study, medical records of 389 patients with TGA were analysed regarding documented precipitating events, which were classified according to previously suggested criteria. Moreover, comorbidities and results of magnetic resonance imaging were collected. FINDINGS: In our cohort of TGA patients, 231 were female (59.4%). A precipitating factor was identified in 266 patients (68.4%). Of these, 136 patients (51.1%) reported physical triggers, the most common being physical exertion (64.0%). Another 122 patients (45.9%) presented with an emotional trigger, most frequently classified as an interpersonal conflict (42.7%). In 8 cases (2.1%), TGA was preceded by a medical procedure. Emotional triggers were more often experienced by women (37.2% vs 22.8%, p = 0.003), while physical stressors were more often present in men (30.7% vs 41.1%, p = 0.035). Women had a significantly higher number of hippocampal MRI lesions than men (mean 1.13 vs 0.92; p = 0.042). CONCLUSION: Our data suggest a female predominance in TGA occurrence and a sex-related difference in susceptibility to certain triggering events in TGA patients. In light of recent research on sex-specific differences in vulnerability to stress, these findings support the hypothesis that this might be a significant contributing factor in the pathogenesis of TGA.

Factors associated with recurrent transient global amnesia: systematic review and pathophysiological insights.

The examination of the risk factors that affect the recurrence of transient global amnesia (TGA) may shed light on the pathophysiological substrate of the disease. A systematic review was performed to identify the factors associated with the recurrence of TGA. MEDLINE, EMBASE, CENTRAL and PsycINFO were meticulously searched. Observational controlled studies involving patients with single (s-TGA) and recurrent TGA (r-TGA) according to Hodges and Warlow's criteria were retrieved. Differences in the demographic characteristics, personal and family medical history, previous exposure to precipitating events and laboratory findings were examined. Retrieved evidence was assessed in the context of the individual article validity, based on the numerical power and methodological quality of each study. Nine cohort studies with retrospective, prospective or mixed design were retrieved. In total, 1989 patients with TGA were included, 269 of whom suffered from r-TGA (13.5%). R-TGA presented an earlier age of onset. Evidence was suggestive of a relationship between recurrence and a family or personal history of migraine, as well as a personal history of depression. There was weaker evidence that associated recurrence with a positive family history of dementia, a personal history of head injury and hippocampal lesions in diffusion-weighted MRI. On the other hand, no connection was found between recurrence and electroencephalographic abnormalities, impaired jugular venous drainage, cardiovascular risk factors, atrial fibrillation, previous cerebrovascular events, exposure to precipitating events, a positive family history of TGA and hypothyroidism. Important pathophysiological insights that arised from these findings were discussed.

Transient global amnesia does not increase the risk of subsequent ischemic stroke: a propensity score-matched analysis.

INTRODUCTION: Data regarding the risk of cerebrovascular events following transient global amnesia (TGA) remain controversial. While some neuroradiological studies suggest an underlying cerebrovascular etiology, results from the clinical studies have been largely conflicting. We, therefore, aimed to evaluate the risk of ischemic stroke in a large, nationally representative sample of patients with TGA. METHODS: We utilized the Nationwide Readmissions Database 2010-2015 to identify all hospitalizations with the primary discharge diagnosis of TGA. We selected a 2% random sample of all elective admissions to be included as controls. A propensity score-matched analysis was performed to match patients with TGA and the controls. The primary outcome was readmission due to ischemic stroke up to 1 year following discharge from the index hospitalization, assessed using the Kaplan-Meier survival analysis in the propensity-matched groups. RESULTS: There were 24,803 weighted hospitalizations due to TGA (mean ± SD age: 65.6 ± 10.4 years, female: 54.9%) and 699,644 corresponding controls. At baseline, patients with TGA were significantly older, more likely to be male, and had a higher prevalence of hypertension, hyperlipidemia, coronary artery disease, cerebrovascular disease, and migraine, as compared to the controls. However, after propensity score matching, we obtained 21,202 cases and 21,293 well-matched corresponding controls, and the risk of readmission due to ischemic stroke in patients with TGA was not different compared to the control group (HR: 1.13, 95% CI 0.62-2.05, P 0.686) during the mean (SD) follow-up period of 192.2 (102.4) days. CONCLUSIONS: After adjustment for demographics and cerebrovascular risk factors, TGA is not associated with an increased risk of subsequent ischemic stroke.

The long-term prognosis of Transient Global Amnesia: a systematic review.

Transient Global Amnesia (TGA) constitutes an enigmatic amnestic condition. In view of the admittedly limited knowledge regarding the nature of TGA, we decided to systematically review existing evidence for the generally regarded benign course of the disease. MEDLINE, EMBASE, CENTRAL and PsycINFO were searched for relevant articles. Observational (case-control, cross-sectional and cohort) controlled studies were retrieved. TGA diagnosis was made according to the diagnostic criteria of Caplan, validated by Hodges and Warlow. The TGA group was compared with either healthy controls (HC) or/and individuals with transient ischaemic attacks (TIA). The long-term risks of dementia, epilepsy, psychological-emotional disturbances, as well as long-term vascular and (vascular or nonvascular) mortality risks, were evaluated. Quality assessment was based on the Newcastle-Ottawa Scale. Literature search provided 12 eligible articles. Retrospective, prospective or mixed cohort designs were implemented in every study. Five articles registered a high quality, five registered a moderate quality, while two articles were assessed as part of the grey literature (conference abstract, abstract in English-article in Spanish). Overall, retrieved evidence was suggestive of similar vascular and mortality risks in TGA patients and HC, while TIA individuals exhibited elevated risks. Moreover, psychological disturbances were comparable between TGA and healthy individuals. On the other hand, studies for dementia and epilepsy obtained contradictory results, indicating both a similar and an increased risk in the TGA group compared to the HC group. Therefore, additional high-quality studies are warranted for the acquisition of more determining conclusions regarding the long-term risk of dementia and epilepsy in TGA.

Conventional cardiovascular risk factors in Transient Global Amnesia: Systematic review and proposition of a novel hypothesis.

Transient Global Amnesia (TGA) is an enigmatic amnestic syndrome. We conducted a systematic review to investigate the relationship between the conventional cardiovascular risk factors and TGA. MEDLINE, CENTRAL, EMBASE and PsycINFO were comprehensively searched and 23 controlled observational studies were retrieved. The prevalence of hypertension, diabetes mellitus, dyslipidemia and smoking was lower among patients with TGA compared to Transient Ischemic Attack. Regarding the comparison of TGA with healthy individuals, there was strong evidence suggesting a protective effect of diabetes mellitus on TGA and weaker evidence for a protective effect of smoking. Hypertension was associated with TGA only in more severe stages, while dyslipidemia was not related. In view of these findings, a novel pathophysiological hypothesis is proposed, in which the functional interactions of Angiotensin-II type-1 and N-methyl-D-aspartate receptors are of pivotal importance. The whole body of clinical evidence (nature of precipitating events, associations with migraine, gender-based association patterns) was integrated.

Prevalence of Mimics and Severe Comorbidity in Patients with Clinically Suspected Transient Global Amnesia.

BACKGROUND: Transient global amnesia (TGA) is a syndrome featuring acute anterograde amnesia as the most striking clinical symptom. Its etiology is still a matter of debate. Most neurological guidelines allow the diagnosis on the basis of clinical criteria only; a more extensive evaluation is recommended only for patients with "red flags" like severe headache, nausea or vomiting, or metabolic abnormalities. The aim of our study was to assess the frequency of a severe underlying disease or alternative diagnoses (mimics) in patients fulfilling the clinical criteria. METHODS: We evaluated the medical records and the imaging data of an unselected consecutive cohort of patients with suspected TGA over a 7-year period. All patients were hospitalized and received a neurological workup including brain imaging, color-coded duplex sonography of the brain supplying arteries, electroencephalography, and laboratory studies of blood and (in selected cases) cerebrospinal fluid. RESULTS: 163 patients with 166 episodes of suspected TGA were hospitalized (3 patients twice). After the workup, the diagnosis of TGA was confirmed in 148/166 (89.2%) episodes ("simple TGA"). Eighteen patients (10.8%) either had an alternative diagnosis or a severe comorbidity that was assumed to have had an impact on the occurrence of the amnestic episode ("complicated TGA/mimic"). The most important differential diagnosis was stroke (11 patients, 6.6% of all TGA suspects and 61.1% of the complicated TGA/mimic group). Other mimics were transient epileptic amnesia (2 patients) and steroid-induced delirium (1 patient). Important comorbidities that had not been obvious at the time of presentation were severe sleep apnea (2 patients), triptan overuse (1 patient), and an involuntary amlodipine intoxication during TGA. CONCLUSION: As approximately every tenth patient with suspected TGA either had an alternative diagnosis or a severe comorbidity, which had not been obvious at the time of admission, we consider in-patient treatment of all suspected TGA cases as appropriate, preferably in the setting of a stroke unit, as ischemic stroke was the by far most important diagnosis mimicking TGA.

The distribution of the transient global amnesia in the province of Ferrara, Italy, a clue to the pathogenesis?

The pathophysiology of transient global amnesia (TGA) is still uncertain. In the province of Ferrara (Fe-province), Italy, given the health organization and the alarming clinical features, the cases of TGA in the resident population virtually correspond to the resident outpatients diagnosed as TGA cases in the ER of the University Hospital of Ferrara. Thanks to this, a retrospective survey identified 35 (14 men, 21 women) first-ever TGA cases in the resident population in 2018 (346,975 inhabitants) giving a crude incidence rate of 10.10/100,000 (95% CI 7.00-14.00), 8.40/100,000 (95% CI 4.60-14.10) for men, and 11.60/100,000 (95% CI 7.20-17.80) for women, a non-significant gender difference. The incident cases of TGA were evenly distributed according to both season and month. The monthly cases of TGA followed the Poisson distribution (goodness-of-fit test: λ = 2.9, χ2 = 2.557, 5 degrees of freedom, p > 0.70). The incidence of TGA in the Fe-province was higher in the highest level of urbanization (21.40/100,000 95% CI 13.10-33.00) than in the lowest one (4.20/100,000 95% CI 1.92-8.00). The incident cases of TGA increased with the level of urbanization (χ2 trend test = 19.940, p < 0.001) and the population density (inhabitants/km2) level (χ2 trend test = 46.684, p < 0.001). Since urbanization is likely involved in stress-related disorders, these findings achieved in a well-defined homogeneous population seem to support the hypothesis of the involvement of stress, maybe in vulnerable individuals, in TGA.

Risk factors predicting recurrence of transient global amnesia.

OBJECTIVE: To assess risk factors of transient global amnesia (TGA) recurrence. METHODS: Retrospective study of a case series of patients with the diagnosis of TGA in our neurology center in the last 8 years, identified through an anonymized database search. TGA was identified by applying Hodges and Warlow criteria. RESULTS: Seventy patients (70% female, average age 64.8 ± 7.8 years) were enrolled; mean follow-up was 16.5 months. More frequent co-morbidities were hypertension (50%), depression (25.7%), diabetes mellitus (17.1%), migraine (15.7%), and cerebrovascular disease (8.6%). Average TGA episode duration was 4 h. Forty-one percent had an identifiable trigger-emotional stress (25.7%), physical effort (8.6%), and sexual intercourse (4.3%). Five patients (7.1%) had hippocampus restriction on diffusion weighted MRI. Nineteen patients (27.1%) had TGA recurrence. Patients with recurrent TGA were more likely to be female and have history of depression, shorter duration episode, and hippocampus hyperintensity on brain MRI. None of the other clinical characteristics and complementary studies were predictors of recurrence. In the multivariate analysis, history of depression was the only factor found to predict which patients had a higher risk of recurrence. CONCLUSION: We present a cohort of TGA patients with a considerable recurrent rate (27%), alerting for the possibility of recurrence of this clinical entity. TGA recurrence was associated with the following factors: female sex, depression, shorter episode duration, and hippocampal hyperintensity on brain MRI. History of depression was found to be the most important recurrence predictor in our study.

Factors Associated With Risk of Recurrent Transient Global Amnesia.

Importance: Transient global amnesia (TGA) is usually considered a benign event with a low recurrence rate. However, recurrence rates vary considerably among studies and there are no known risk factors for TGA. Objective: To examine risk factors for the recurrence of TGA. Design, Setting, and Participants: This retrospective cohort study involved medical record review of patients with isolated or recurrent TGA presenting to the Mayo Clinic in Rochester, Minnesota, between August 1, 1992, and February 28, 2018. A total of 1491 cases were reviewed and 1044 met diagnostic inclusion criteria for TGA, with the remainder excluded owing to indeterminate or alternate diagnoses or limited information available in the medical record. Exposures: Single vs recurrent episodes of TGA. Main Outcomes and Measures: Demographics, precipitating factors, migraine history, imaging and electrodiagnostic findings, and family history of TGA were collected. The main outcome measure was TGA recurrence. Results: Of 1044 included patients, 575 (55.1%) were male, and the mean (SD) age at inclusion was 75.0 (11.5) years. A total of 901 patients (86.3%) had a single episode of TGA and 143 (13.7%) had recurrent episodes of TGA. The 2 groups were similar in age at inclusion, sex, identifiable triggers, and duration of anterograde amnesia. The number of recurrences ranged from 1 to 9, with 137 individuals (95.8%) having 3 or fewer recurrences. The mean (SD) age at first episode of TGA was 65.2 (10.0) years for individuals with a single episode vs 58.8 (10.3) years for those with recurrent episodes (P < .001). There was a personal history of migraine in 180 individuals (20.0%) with a single episode of TGA and 52 individuals (36.4%) with recurrent episodes of TGA (P < .001), and a family history of migraine in 167 individuals (18.5%) with a single episode of TGA and 44 individuals (30.8%) with recurrent episodes of TGA (P = .001). There were no electroencephalographic findings associated with increased risk of TGA recurrence. Acute and subacute temporal lobe abnormalities on results of magnetic resonance imaging were seen rarely and did not require intervention. A family history of TGA was identified in 12 individuals (1.3%) with a single episode of TGA and 4 individuals (2.8%) with recurrent episodes of TGA. Conclusions and Relevance: This study suggests that, in this large cohort of patients with TGA, recurrent TGA was associated with earlier age at the time of first TGA episode and higher prevalence of both personal and family history of migraine compared with isolated cases. These results can be used to counsel patients about risks of recurrence and may have implications for the understanding of TGA pathophysiology.

Transient Global Amnesia - Risk Factors and Putative Background.

OBJECTIVES: Transient global amnesia (TGA) is a temporary short-term reversible memory loss. Etiology of TGA remains unclear with various hypotheses. We analyzed clinical characteristics, neuroimaging, and electrophysiological findings as well as comorbidities and seasonal variation in TGA patients with regard to possible background of the syndrome. MATERIALS AND METHODS: A total of 56 patients (42 women and 14 men) with TGA hospitalized from 2008 to 2016 in the Department of Neurology, Wroclaw Medical University. RESULTS: A total of 52 patients (92.9%) underwent their first-ever episode of TGA. The potential triggers or events before episode could be recognized in 22 patients (39.3%). 35.7% patients had TGA in summer and 26.8% in winter months. In 92.9% patients chronic diseases were found, included: Hypertension (60.7%), dyslipidemia (48.2%), autoimmune thyroiditis (17.9%), and ischemic heart disease (14.3%). One patient (1,8%) suffered from migraine. Doppler ultrasonography of carotid arteries revealed abnormalities in 29 patients (51.8%). Electroencephalography abnormalities were observed in 10 (17.6%) of patients. CONCLUSION: Our findings suggest a putative cerebrovascular background of transient global amnesia. No evidence has been provided for the association between TGA and epilepsy or migraine. Among comorbidities, autoimmune thyroiditis deserves further investigation with regard to its potential links with TGA.